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Shift Solenoid 1 and 2 3. Place the gear selector in the DRIVE position. 4. Accelerate the vehicle using the chosen throttle position. Hold the throttle steady. 5. As the transmission upshifts, there should be a noticeable shift feel or engine speed change within 1 to 2 seconds of the commanded gear change. The TCC feel may not be noticeable. 6. Compare the shift speeds to the Shift Speed table. Refer to Shift Speed . Shift speeds may vary slightly due to TFT or other operating variables, including hydraulic delays in Note any harsh, soft or delayed shifts or slipping. Note any noise or vibration. 7. Monitor TCC PC solenoid current while driving and make sure the current rises when the TCC is commanded to apply. When the TCC applies there should be a noticeable drop in engine speed and a drop in Check for DTCs. Refer to Torque Converter Diagnosis. Apply and release the brake pedal. The TCC will release on most applications. PART THROTTLE DETENT DOWNSHIFT IMPORTANT: This transmission is equipped with an electronically controlled capacity clutch (ECCC), which does not allow the IMPORTANT: The TCC will not engage until the engine is in closed loop operation and the vehicle speed is as shown in the Shift
2008 Chevrolet Silverado 1500 2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
1. Place the gear selector in the DRIVE position. 2. Accelerate the vehicle to 64-88 km/h (40-55 mph) in 6th gear. 3. Quickly increase throttle angle to between 25-30 percent. 4. Verify the following: The TCC releases. The transmission downshifts immediately. MANUAL DOWNSHIFTS Manual downshift testing is not required for vehicles equipped with Driver Shift Control (DSC). COASTING DOWNSHIFTS 1. Place the gear selector in the DRIVE position. 2. Accelerate the vehicle to 6th gear with the TCC applied. 3. Release the throttle and apply the brakes 4. Verify the following: The TCC releases (on most applications). Downshifts occur as commanded. MANUAL GEAR RANGE SELECTION This application does not utilize manual forward gear ranges. Reverse Perform the following test using a 10-15 percent throttle position. 1. With the vehicle stopped, move the gear selector to REVERSE. 2. Slowly accelerate the vehicle. 3. Verify that there is no noticeable slip, noise or vibration. Driver Shift Control (DSC) Refer to the owner's manual for specific instructions on DSC. The TCM will upshift
2008 Chevrolet Silverado 1500 2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
TORQUE CONVERTER DIAGNOSIS The torque converter clutch (TCC) is applied by fluid pressure, which is controlled by a TCC TORQUE CONVERTER STATOR The torque converter stator roller clutch can have 2 different malfunctions. The stator assembly freewheels in both directions. The stator assembly remains locked up at all times. POOR ACCELERATION AT LOW SPEED If the stator is freewheeling at all times, the vehicle tends to have poor acceleration from a If the engine freely accelerates to high RPM in NEUTRAL, you can assume that the engine and POOR ACCELERATION AT HIGH SPEED If the stator is locked up at all times, performance is normal when accelerating from a standstill. If the converter has been removed, you can check the stator roller clutch by inserting a finger into NOISE IMPORTANT: Do not confuse this noise with pump whine noise, which is usually noticeable in PARK, NEUTRAL and all other gear ranges.
2008 Chevrolet Silverado 1500 2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
You may notice a torque converter whine when the vehicle is stopped and the transmission is in Perform a stall test to make sure the noise is actually coming from the converter: 1. Place your foot on the brake. 2. Put the gear selector in DRIVE. 3. Depress the accelerator to approximately 1,200 RPM for no more than six seconds. A torque converter noise will increase under this load. TORQUE CONVERTER CLUTCH SHUDDER The key to diagnosing torque converter clutch (TCC) shudder is to note when it happens and TCC shudder which is caused by the transmission should only occur during the apply or the IF SHUDDER OCCURS DURING TCC APPLY OR RELEASE If the shudder occurs while the TCC is applying, the problem can be within the transmission or Something is not allowing the clutch to become fully engaged. Something is not allowing the clutch to release. The clutch is releasing and applying at the same time. One of the following conditions may be causing the problem to occur: Leaking turbine shaft seals A restricted release orifice A distorted clutch or housing surface due to long converter bolts Defective friction material on the TCC plate NOTE: You may damage the transmission if you depress the
2008 Chevrolet Silverado 1500 2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
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